Method of process controller optimization in a multivariable predictive controller

Abstract

In a process control system, having a controller for providing robust control of a process, the controller utilizes a predetermined range control procedure the results being a control solution. The process has at least one manipulated variable and at least one controlled variable. A method of providing dynamic optimization comprises the steps of calculating an optimized set of steady state values of the manipulated variables and the controlled variables. An augmented range control procedure is created to harmonize the set of steady state values with the control solution. The augmented range control procedure is solved, the manipulated variables generated thereby being compatible with the set of steady state values and with the control solution. The process is controlled in accordance with the manipulated variables generated by the augmented range control procedure, thereby providing optimal control of the process.

What is claimed is: 
     
       1. In a process control system, having a controller for providing robust control of a process, the controller utilizing a predetermined range control procedure, the results being a control solution, further the process having at least one manipulated variable and at least one controlled variable, a method of providing dynamic optimization comprising the steps of: a) calculating an optimized set of steady state values of the manipulated variables and the controlled variables.   b) creating an augmented range control procedure to harmonize the set of steady state values with the control solution;   c) solving the augmented range control procedure, the manipulated variables generated thereby being compatible with the set of steady state values and with the control solution; and   d) controlling the process in accordance with the manipulated variables generated by the augmented range control procedure, thereby providing optimal control of the process.   
     
     
       2. In a process control system, the method of claim 1 wherein the step of calculating comprises the step of calculating an optimized set of steady state variables of the manipulated variables and the controlled variables utilizing a quadratic steady state optimization expression. 
     
     
       3. In a process control system, the method of claim 1 wherein the step of solving includes dynamic input parameters of the process control system, the dynamic input parameters including setpoints, hi/lo limits, and system disturbances whereby the step of solving provides optimal manipulated variables resolved by the augmented range control procedure that are compatible with the set of steady state values and with the control solution. 
     
     
       4. In a process control system, the method of claim 1 wherein the step of solving further includes a selectable weighting matrix selected such that neither the optimized set of steady state values nor the control solution is predominant in the manipulated variables generated by the augmented range control procedure.